WordPress have previously always asked for title text when adding a link, but from version 4.2 they’ve abandoned this.
I wrote an article about how bad the title tag is for accessibility, because some web developers assume this is read aloud by screenreaders, bit it isn’t. I wrote an article about this here: I thought title tag improved accessibility, I was wrong.
I learned this after pretending to be blind for a week, and learning how to use a screenreader. I learned loads, and recommend every web developer to do the same!
Image above is from this article which is where I was first alerted about WordPress’ change.